Question: A number is increased by $50\%$ and then the result is decreased by $50\%$. What is the percent of decrease from the original number to the final number?
Explanation: Call our original number $x$. After a $50\%$ increase, $x$ becomes $1.5x$, and after a further $50\%$ decrease, $1.5x$ becomes $.75x$. Thus, there is a decrease of $\boxed{25\%}$ from the original number.